This output type allows you to control a state of selected and configured outputs. When you change the “Group switch” state, it reflects on all grouped outputs. So, you can control several outputs by one command.

Group switch examples

The configuration above allows you to control Output 2 and 3 using one switch connected to Input 1.

The firmware does not control the state of a pin assigned to Output 1 (P01 in this example). You can use any unused pin for the group switch.

Group switch waveform diagram

If you disable the “Switch” option for Input1, the waveform diagram will look like this:

Group switch with a clickable button

Limit switch

In the “Limit switch” mode, you can send any signal to the “Group switch” output, and the firmware switches off all grouped outputs. It is useful to link this output with an alarm input (for example, a water leak sensor).

Limit switch

Interlock mode

The “Interlock” feature prevents two or more GPIO outputs from being active at the same time. The group switch with the “Interlock” mode allows you to define “interlocking group” with a list of all the switches in the group. If one of the switches in the group changes state to “ON,” the firmware sets all other switches to OFF.

The firmware allows setting all switches to the OFF state.

You can send the OFF command on the endpoint with the group switch to change the state of all switches in the group to “OFF.”

Inverted interlock mode

If one of the switches in the group changes state to “OFF,” the firmware sets all other switches to ON.


It is a software interlock, and a software bug can still activate both switches simultaneously. Similarly, at reset time (before firmware code runs), the relay GPIO pins may have pull-ups active, so the relay may be active before the firmware initialize them.

So it is highly recommended to use hardware interlocks (like SPDT-type relays) to ensure that two GPIOs are never active simultaneously.

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